Navigation on the Compass is accomplished with a Lowrance X-15 differential GPS. The X-15 is interfaced to a laptop computer for real-time data acquisition of position, heading, velocity, and bottom depth. National Instruments LabView control software is used to coordinate navigation data from the X-15 with water column data obtained from a YSI 6920 in situ sensor measuring oxygen, pH, pE, conductivity, temperature, pressure, and fluorescence.